You can import a single icon or a folder containing icons through the command line.
iconimport -repo <repo name> -i <Icon file or folder> -f] (Force overwrite)
Example
jre\bin\Java -Xmx512m -XX:MaxMetaspaceSize=512m -splash: -jar WhereScape-3D-HEAD-bundle.jar iconimport -repo "Local repository" -i "C:\temp\icon.png"